This project is designed to isolate genes specifically expressed by human pancreatic beta islet cells which regulate glucose metabolism and play a major role in Insulin-Dependent Type-1 Diabetes Mellitus (IDDM). Our strategy was to prepare subtraction library. Briefly, two libraries were made: one from insulinoma (beta cell tumor) and the other from glucagonoma (alpha cell tumor). Then, we subtracted the glucagonoma library from the insulinoma library. Each residual cDNA clone was screened against different RNAs isolated from various organs. Two novel cDNA clones (IG-34 and IG-134A) were selected. Double-strand sequencing of 1.5 Kb IG-34 insert showed no homology with published DNA sequence stored in GenBank. Both mouse and rat counterparts of IG-34 were also isolated by cross- hybridization with the human clone. Functional studies of IG34 expression are currently in progress.